Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/tmag.2022.3201898

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/tmag.2022.3146058

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/tmag.2021.3114690

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/tmag.2021.3113904

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/intermag42984.2021.9579866

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/intermag42984.2021.9579979

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/tmag.2020.3027253

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/tmag.2020.3030300

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/tmag.2020.3011163

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/tmag.2020.3012156

researchmap

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)  

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/tmag.2019.2936238

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/TMAG.2019.2891711

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

© 1965-2012 IEEE. The 3-D magnetic recording using the microwave-assisted magnetic recording and a spin-torque oscillator as a reading sensor has been proposed as a candidate of the prospective recording technologies. In our previous research, we have constructed the read/write channel of the envelope model to evaluate a variety of signal processing for the 3-D magnetic recording. In this paper, we apply the low-density parity-check coding and iterative decoding system including turbo equalization to the 3-D magnetic recording channel model with dot position fluctuation and evaluate the bit error rate performance by the computer simulation. The results clarify that the tolerance of dot position fluctuation which 'no errors' is able to be achieved.

DOI： 10.1109/TMAG.2019.2891299

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers (IEEE)  

DOI： 10.1109/TMAG.2018.2833167

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Institute of Physics Inc.  

In this article, we propose the detection method of the recorded data pattern by the envelope of the temporal magnetization dynamics of resonantly interacting spin-torque oscillator on the microwave assisted magnetic recording for three-dimensional magnetic recording. We simulate the envelope of the waveform from recorded dots with the staggered magnetization configuration, which are calculated by using a micromagnetic simulation. We study the data detection methods for the envelope and propose a soft-output Viterbi algorithm (SOVA) for partial response (PR) system as a signal processing system for three dimensional magnetic recording.

DOI： 10.1063/1.5006105

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

The shingled magnetic recording (SMR) system is influenced by not only jitter-like medium noise from adjacent bits in the down-track direction but also intertrack interference (ITI) from the adjacent tracks. In this paper, we investigate the relationship between the recording pattern and the decoding reliability by classifying the log-likelihood ratio at the a posteriori probability decoder output according to the recording patterns under an SMR R-W channel specification of 4 Tb/in(2) by computer simulation. The result shows that the decoding reliability for the recording pattern "010" heavily affected by transition jitter is the lowest and little improved even if the influence of ITI is mitigated by a 2-D finite-impulse response filter.

DOI： 10.1109/TMAG.2017.2721428

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

Two-dimensional magnetic recording (TDMR), which combines shingled magnetic recording (SMR) with 2-D signal processing attracts attention from the hard disk drive industry. SMR is a magnetic recording system in order to increase the track density by writing tracks without the guard band. Therefore, the influences of writing and reading intertrack interferences (ITIs) deteriorate the quality of reproducing waveforms. Additionally, degradation of track due to overwriting and crosstalk from the adjacent tracks due to the width of reader sensitivity. The equalization using 2-D finite impulse response filter for the waveforms from three adjacent tracks is proposed as a method to reduce the influence of reading ITIs. In this paper, we evaluate the bit aspect ratio (BAR) in TDMR read/write channel under a specification of 4 Tb/in(2) using bit error rate of the low-density parity-check (LDPC) coding and iterative decoding system obtained by computer simulation. The results show that the suitable BAR in array head reading is 2.0.

DOI： 10.1109/TMAG.2017.2701355

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

This paper proposes a utilization of multiple read heads to predict and correct a track mis-registration (TMR) in bit-patterned media recording (BPMR) based on the readback signals. We propose to use the signal energy ratio between the upper and lower tracks from multiple read heads to estimate the TMR level. Then, a pair of two-dimensional (2D) target and its corresponding 2D equalizer associated with the estimated TMR will be chosen to correct the TMR in the data detection process. Numerical results show that the proposed system can achieve a very high accuracy of TMR prediction, thus performing better than the conventional system, especially when TMR is severe. (C) 2016 Author(s).

DOI： 10.1063/1.4972801

Web of Science

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

The 2-D magnetic recording (TDMR) by shingled magnetic recording (SMR) draws attention as a technology to increase the recording densities in a hard disk drive. The magnetization pattern is curved by the write field at the corner of the writer in SMR, and the information to read/write (R/W) channel performance is feared. Therefore, it is possible that the bit error rate performance is improved by fitting the reader sensitivity to the bit shape. In this paper, we evaluate the effect of reader sensitivity rotation in the TDMR R/W channel with head skew under a specification of 4 wTb/in(2) by computer simulation, applying the low-density parity-check coding and the iterative decoding system with the 2-D finite impulse response filter. The results show that the rotated reader sensitivity fits the recorded bit magnetization shape, and the error-free skew range increases to -3 degrees similar to 6 degrees. Therefore, the reader sensitivity rotation is considered to be an effective way to improve the skew margin in the TDMR system.

DOI： 10.1109/TMAG.2016.2531088

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

The move from traditional single-track magnetic recording to two-dimensional magnetic recording (TDMR) with squeezed tracks and multiple readers opens up new design degrees of freedom beyond the track pitch and bit-aspect ratio, including the widths, spacing, and crosstrack positions of the readers. In this paper, we present a systematic method for determining the combination of multi-reader geometry, track pitch, and bit-aspect ratio that maximizes the areal density of a TDMR system using single-track detectors. The method combines realistic modeling of the medium and write/read processes, advanced signal detection, and information-theoretic tools. For the particular head and medium we consider, the two-reader geometry that maximizes areal density with zero skew and zero misregistration was found to use different-sized readers (the smaller having a full-width at half-maximum width, i.e., 96% of the track pitch and the larger having a width, i.e., 148% of the track pitch) with significant overlap in the crosstrack direction (centers spaced by one eighth of the track pitch). The optimal bit-aspect ratio was 2.2. At the optimal operating point, the information rate per coded bit is 0.8.

DOI： 10.1109/TMAG.2015.2483593

Web of Science

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

2-D magnetic recording (TDMR) exploits 2-D signal processing using the waveforms reproduced by array head from the intended and adjacent tracks to mitigate the effects of intertrack interference. However, an array head has the issue on the degradation of bit error rate (BER) performance due to head skew. In this paper, we evaluate the BER performance of TDMR R/W channel with head skew under a specification of 4 Tbit/in(2) employing low-density parity check coding and iterative decoding system using a 2-D finite-impulse response filter by computer simulation. The results show that our system can achieve the reliable BER performances by appropriately setting the reader scanning positions at the head skew angle between 0 degrees and 3 degrees.

DOI： 10.1109/TMAG.2015.2445372

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

A timing recovery method for a high-density tape storage system is studied in this paper. Since tape systems suffer from large speed variations compared with disk systems, the design of a stable timing recovery scheme that can operate under low signal-to-noise ratio (SNR) conditions is important. In such low SNR scenarios, decision errors made by the detector occasionally cause the phase-locked loop circuit to lose track of the correct signal, which is often called the loss-of-lock (LOL) phenomenon. In order to mitigate the LOL issue, soft information from the Viterbi detector is utilized. It is clarified that the negative effect of unreliable decisions from the detector can be compensated for by dynamically controlling the feedback gain of the timing recovery loop as a function of decision reliability. It is shown that the LOL rate performance can be improved by this approach, with only a minor increase in the implementation complexity.

DOI： 10.1109/TMAG.2015.2439059

Web of Science

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

The two-dimensional magnetic recording (TDMR) exploits two-dimensional signal processing using the neighboring read-back waveforms. We allocate dual readers for the intended tracks and evaluate the effects of head skew angle on the bit error rate performance in partial response class-I maximum likelihood system with a two-dimensional finite impulse response filter using two read-back waveforms under TDMR R/W channel specifications of 4 Tbit/in.(2). The results show that the effect of positive skew angle is larger than that of negative skew angle, and the center of skew angle should be shifted to minus direction. (C) 2015 AIP Publishing LLC.

DOI： 10.1063/1.4906965

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER INST PHYSICS  

Two-dimensional magnetic recording is affected by the inter-track interference (ITI) from the adjacent tracks. We investigate the improvement of partial response maximum likelihood (PRML) systems with signal dependent noise predictor (SDNP) in the bit error rate performance. The systems reduce the influence of ITI by two dimensional finite impulse response filter using the waveforms reproduced by triple readers from the adjacent tracks. The results show that the SDNP provides larger improvement to PR(2,6,1)ML system compare with PR1ML system. (c) 2015 AIP Publishing LLC.

DOI： 10.1063/1.4908145

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers Inc.  

This paper presents the results of a comprehensive study of the shingled writing process and various signal processing and data detection approaches applied to the readback waveforms. The recording simulations include realistic head fields, a random granular media, magnetostatic and exchange interactions, and a READ head sensitivity function. Readback waveforms are examined in both one and two dimensions in terms of signal characteristics (linear and nonlinear), noise behavior (stationary and signal-dependent), and intertrack interference. Different equalization and detection approaches are compared and about a 10% density gain is reported for such 2-D magnetic recording compared with traditional single-track recording. These gains depend strongly on the number of readers, the reader positioning, and the reader width.

DOI： 10.1109/TMAG.2014.2356455

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers Inc.  

The two-dimensional magnetic recording (TDMR) by shingled magnetic recording needs two-dimensional (TD) signal processing using the multiple read-back waveforms. In this paper, to allocate dual readers (reader 1 and 2) for the intended tracks, we evaluate the bit error rate (BER) performance of a low-density parity-check coding and iterative decoding system with a TD-finite impulse response equalizer under TDMR R/W channel specifications of 4 Tb/in \\(^{2}\\). Here, the TDMR R/W channel is modeled using a discretized granular medium and the writing process based on a slope model considering the media switching field angle given by the Stoner-Walfarth reversal mechanism. The result shows that to affect the good BER performance, the reader 1 should be placed slightly toward the next track from the center of the home track, and the reader 2 should be placed around the boundary between the home and following tracks.

DOI： 10.1109/TMAG.2014.2318335

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：American Institute of Physics Inc.  

In this paper, we investigate the influence of the writing and reading intertrack interferences (ITIs) in terms of bit aspect ratio (BAR) in shingled magnetic recording by computer simulation using a read/write model which consists of a writing process based on Stoner-Wohlfarth switching asteroid by a one-side shielded isosceles triangular write head and a reading process by an around shielded read head for a discrete Voronoi medium model. The results show that BAR should be 3 to reduce the influence of writing and reading ITIs, media noise, and additive white Gaussian noise in an assumed areal density of 4.61Tbpsi. © 2014 AIP Publishing LLC.

DOI： 10.1063/1.4866393

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

A 2-D magnetic recording (TDMR) by shingled magnetic recording (SMR) is one of the most promising technologies for realizing ultra-high areal densities. We have developed the discretized granular medium model with nonmagnetic grain boundaries and the simple writing process considering intergranular exchange fields and magnetostatic interaction fields between grains on the discrete Voronoi model for TDMR. In this paper, the bit-error rate (BER) performance of the iterative decoding system using a nonbinary low-density parity-check (LDPC) code over Galois field GF(q) with the 2-D finite-impulse-response equalizer (2D-FIRE) is obtained via computer simulation using an R/W channel model employing the writing process under TDMR specifications of 4.12 Tb/in 2, and it is compared to that with the 1-D FIRE (1D-FIRE). The results show that the BER performance of the nonbinary LDPC coding and iterative decoding system with the 2D-FIRE is better than that with the 1D-FIRE. © 1965-2012 IEEE.

DOI： 10.1109/TMAG.2012.2220532

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

In this paper, the influence of the intertrack interference (ITI) at writing in shingled magnetic recording (SMR) as well as at reading is examined using a read/write model based on recording on a medium composed of discrete Voronoi diagram by a triangular writer with trailing and one-side shields. Two kinds of ITI's at writing which affect the magnetic grains on the track currently being written and the previously recorded track are shown. One is that a part of signal on the previously recorded track remains on the current track due to lack of writing ability of writer. Another is that a part of signal is erased by the next-track writing. The effects are caused from the adjacent tracks at writing. Additionally the ITI at reading deteriorates the read-back waveform. Consequently these ITI's bring the decoding errors. The results by computer simulation using above R/W model show that the decoding errors occur in the low density parts of track which were originally considered to be hard to make errors. © 1965-2012 IEEE.

DOI： 10.1109/TMAG.2013.2242439

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electronics, Information and Communication, Engineers, IEICE  

Bit-patterned medium (BPM) is one of the promising approaches for ultra-high density magnetic recording systems. However, BPM requires precise write synchronization, and exhibits write-errors due to insufficient write field gradient, medium switching field distribution (SFD), demagnetization field from adjacent islands, and island position variation. In this paper, an iterative decoding system using a non-binary low-density parity-check (LDPC) code is considered for a BPMR/Wchannel with write-errors at an areal recording density of 2 Tbit/inch2 including the coding rate loss. The performance of the iterative decoding system using the non-binary LDPC code over the Galois field GF(28) is evaluated by computer simulation, and it is compared with the conventional iterative decoding system using a binary LDPC code. The results show that the non-binary LDPC system has a larger write margin than the binary LDPC system. Copyright © 2013 The Institute of Electronics, Information and Communication Engineers.

DOI： 10.1587/transele.E96.C.1497

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Two-dimensional magnetic recording (TDMR) by shingled magnetic recording (SMR) is one of the most promising technologies for realizing high areal densities. The read/write (R/W) channel model based on a discrete Voronoi model is relatively easily implemented to evaluate the performance of signal processing for TDMR. The nonbinary low-density parity-check (LDPC) coding and iterative decoding system provides the better performance compared with the conventional binary LDPC coding system. Furthermore, a two-dimensional equalizer (2D-EQ) can mitigate the influence of the intertrack interference (ITI) in TDMR. In this paper, the symbol-by-symbol turbo equalizer which consists of a symbol-by-symbol a posteriori probability (APP) decoder for a generalized partial response class-I (GPR1) channel with a 2D-EQ and a sum-product (SP) decoder for a nonbinary LDPC coder over Galois field of GF(28) is evaluated by computer simulation at an areal recording density of 4.12 Tbit/in2. The result shows that the symbol-by-symbol turbo equalizing system provides an SNR improvement of about 3.7 dB over the bit-by-bit turbo equalizing system. © 2013 IEEE.

DOI： 10.1109/TMAG.2013.2245863

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

A neuro intertrack interference canceller (neuro-ITIC) is proposed to diminish the influences of ITI and jitter-like medium noise for two-dimensional magnetic recording (TDMR) by shingled magnetic recording. The bit error rate (BER) performance of a low-density parity-check coding and iterative decoding system including a generalized partial response class-I channel with the neuro-ITIC is also obtained via computer simulation using a read/write channel model under TDMR specifications of 4 Tb/in2, and it is compared to those for a two-dimensional neural network equalizer (2D-NNE) and an ITI canceller (ITIC) with a one-dimensional finite impulse response equalizer (1D-FIRE). It is clarified that the BER performance for the neuro-ITIC is far superior to those for the 2D-NNE and the ITIC with the 1D-FIRE. © 2013 IEEE.

DOI： 10.1109/TMAG.2013.2242437

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electronics, Information and Communication, Engineers, IEICE  

The previously-proposed model of the writing process in TDMR is modified based on the Stoner-Wohlfarth reversal mechanism. The BER performance for a neuro-ITI canceller is obtained via computer simulation using the R/W channel model based on the writing process, and it is compared to those for well-known TDMR equalization techniques. Copyright © 2013 The Institute of Electronics, Information and Communication Engineers.

DOI： 10.1587/transele.E96.C.1504

Scopus

researchmap

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

researchmap

Other Link： http://dblp.uni-trier.de/db/conf/isita/isita2012.html#conf/isita/NakamuraOOAM12

Language：English   Publishing type：Research paper (international conference proceedings)  

A simple writing process considering magnetic clusters due to exchange coupling between grains is studied for two-dimensional magnetic recording. The bit error rate (BER) performance of a low-density parity-check coding and iterative decoding system with a two-dimensional neural network equalizer (2D-NNE) that can diminish the influences of jitter-like medium noise and inter-track interference is obtained using a read/write channel model based on the proposed writing process, and it is compared with those for one- and two-dimensional finite impulse response equalizers (FIREs). It is clarified that the BER performance for the 2D-NNE is far superior to those for the FIREs. © 2012 American Institute of Physics.

DOI： 10.1063/1.3680535

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

It is expected for the nonbinary low-density parity-check (LDPC) coding and iterative decoding system to introduce the turbo equalization in order to enhance the error correction ability in the bit-patterned medium (BPM) R/W channel. In this paper, we investigate the effect of the turbo equalization on the bit-error rate (BER) performance of nonbinary LDPC coding and iterative decoding system over Galois filed GF(2 8) in BPM R/W channel with write-error at an areal recording density of 2 Tbit/inch 2 considering the coding rate loss. The performance of turbo equalization using the nonbinary LDPC coding and iterative decoding system is evaluated by computer simulation, and it is compared to that without turbo equalization. The results show that the nonbinary LDPC and iterative decoding system with the turbo equalization has the larger write-margin compared to that without turbo equalization. © 2012 IEEE.

DOI： 10.1109/TMAG.2012.2194989

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

The write-margin of the iterative decoding systems for the binary and non-binary low-density parity-check (LDPC) codes are studied in the magnetic recording system using a bit-patterned medium (BPM) R/W channel with write-errors caused by the write-head field gradient, the media switching field distribution (SFD), the magnetization fields from adjacent islands, and the island position deviation. The performances of iterative decoding systems using the binary and non-binary LDPC codes are evaluated by computer simulation at an areal recording density of 2 Tb/inch2. The results show that the non-binary LDPC coding and iterative decoding system improves the write-margin compared with the binary LDPC system. Furthermore it is clarified that in order to obtain the sufficient write-margin, it is important to suppress the influence of the demagnetization fields from adjacent islands. © 2012 IEEE.

DOI： 10.1109/GLOCOM.2012.6503609

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

In this paper, the iterative decoding system using the nonbinary low-density parity-check (LDPC) code is studied in the magnetic recording system using a bit-patterned media (BPM) R/W channel affected by the write head field gradient, the media switching field distribution (SFD), the demagnetization field from adjacent dots, and the dot position deviation in an areal recording density of 2 Tb/in2. The performance of iterative decoding system using the nonbinary LDPC code over Galois field of GF(28) is evaluated by the computer simulation, and it is compared with the conventional iterative decoding system using the binary LDPC code. The results show that the nonbinary LDPC system provides better performance compared with the binary LDPC system. © 2011 IEEE.

DOI： 10.1109/TMAG.2011.2147766

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

An accurate medium modeling method of discretized granular medium with non-magnetic grain boundaries using a discrete Voronoi diagram is proposed for two-dimensional magnetic recording. A simple closed-form representation of a double-shielded reader sensitivity function is also proposed for modeling the reading process. Moreover, a two-dimensional neural network equalizer (2D-NNE) is proposed to mitigate the influence of intertrack interference and jitter-like medium noise. The bit-error rate performance of partial response class-I maximum likelihood (PR1ML) system with the 2D-NNE is obtained by computer simulation based on the proposed read/write channel model. The performance is far superior to that of PR1ML system with a two-dimensional finite impulse response equalizer. © 2011 IEEE.

DOI： 10.1109/TMAG.2011.2157808

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

The performance of an iterative decoding system is evaluated in shingled magnetic recording (SMR). The medium model is made by a discrete Voronoi model, and the 2-D sensitivity function of reader is used to obtain the reproducing waveform. As the sensitivity function extends to adjacent tracks, intertrack interference (ITI) deteriorates the signal detection system. In order to recover the intrinsic performance, it is required to reduce the influence of ITI to the system. Then, the ITI canceller is employed to combat ITI for the iterative decoding system, and the performance is evaluated by computer simulation. The results show that the introduction of ITI canceller improves the bit-error-rate performance in SMR system. © 2011 IEEE.

DOI： 10.1109/TMAG.2011.2158075

Scopus

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

The neural network equalizer (NNE) matched to recording code is proposed to reduce the influence of interpixel interference in holographic data storage (HDS). A searching method is proposed to proceed simultaneously with the search of a conversion table of the 5-9 recording code and the search of simplified NNE by using hybrid genetic algorithm. Furthermore, the bit error rate performance of HDS system is obtained. The result shows that the proposed method is superior in the performance to the conventional method. © 2011 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.50.09MB05

Scopus

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Elsevier B.V.  

Shingled magnetic recording attracts much attention as a new recording system for hard disk drive to make the narrower track than the writer-track-width. However, the issue for reading by a wider reader than the track width on the media remains, and the inter-track interference (ITI) from adjacent tracks causes the performance deterioration. To recover the performance, in this paper, we propose an ITI canceller for the reproduced waveform from shingle-recorded tracks, and evaluate the performance of the PRML channel. © 2011 Published by Elsevier B.V.

DOI： 10.1016/j.phpro.2011.06.112

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Elsevier B.V.  

The neural network equalizer (NNE) for the generalized partial response maximum likelihood (GPRML) system with a postprocessor in perpendicular magnetic recording is studied. First, a new designing method of NNE is proposed for suppressing frequency of a high-level noise at the discrimination point which degrades the bit error rate (BER) performance of the GPRML system with a post-processor. Then, the BER performance of GPR class-1 ML system with a post-processor using the NNE is obtained and compared with that using a conventional transversal filter as an equalizer. The result shows that the gain of the former over the latter is about 0.6 dB at a BER of 10-5. © 2011 Published by Elsevier B.V.

DOI： 10.1016/j.phpro.2011.06.111

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electronics, Information and Communication, Engineers, IEICE  

In this paper, we propose a new method to estimate and effectively reduce the effect of thermal asperity (TA) in the perpendicular magnetic recording (PMR) channels with the state trellis. The TA is estimated from the state trellis, then its average is used to modify the equalized signal entering the Viterbi detector. For the partial response (PR) targets with DC component, the proposed method with a maximum-likelihood detector can improve the bit error rate performance by more than an order of magnitude when TA occurs and degrades when the giant magneto-resistive (GMR) nonlinearity and base line wander (BLW) effects are present. Unlike the previous studies, this method allows the use of PR targets with DC component under the presence of TA. Copyright © 2011 The Institute of Electronics, Information and Communication Engineers.

DOI： 10.1587/transele.E94.C.1472

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Elsevier B.V.  

We evaluate the performance of the write-margin for the low-density parity-check (LDPC) coding and iterative decoding system in the bit-patterned media (BPM) R/W channel affected by the write-head field gradient, the media switching field distribution (SFD), the demagnetization field from adjacent islands and the island position deviation. It is clarified that the LDPC coding and iterative decoding system in R/W channel using BPM at 3 Tbit/inch 2 has a write-margin of about 20%. © 2011 Published by Elsevier B.V.

DOI： 10.1016/j.phpro.2011.06.113

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

The neuro-interpolator (NI) integrating the interpolator with neural network equalizer is proposed to reduce the influence of interpixel interference in holographic data storage. The simplification of NI is performed by using a hybrid genetic algorithm based on a new mutation method. The bit error rate performance of the simplified NI is superior to that of the interpolator alone. Furthermore, the number of connections in the simplified NI is reduced to about half of that obtained by using a conventional mutation method. (C) 2010 The Japan Society of Applied Physics

DOI： 10.1143/JJAP.49.08KD10

Web of Science

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

In this paper, low-density parity-check (LDPC) coding and iterative decoding system is studied in the magnetic recording system using a bit-patterned medium (BPM). The magnetic recording system using BPM has a serious problem of requiring precise write synchronization to correctly write the recording sequence on each intended island. In this paper, an error locator using the parity-check matrix of LDPC code is utilized to curb the influence of write error on the iterative decoding process. The performance of the proposed system with the error locator is evaluated by computer simulation for magnetic recording system using BPM with synchronization write error at a recording density of 2 Tb/in(2) and it is compared with a conventional Reed-Solomon (RS) encoding and decoding system. The results show that the proposed system provides better performance.

DOI： 10.1109/TMAG.2009.2022331

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

In this paper, a new burst detection method using the check matrix of low-density parity-check (LDPC) code is proposed. The burst detection for the bit flipping burst-like signal degradation which the conventional burst detection using a reproducing waveform, an equalizer output, an a posteriori probability (APP) decoder output and so on cannot detect is studied. The performance of the LDPC coding and iterative decoding system with the proposed burst detector is evaluated by computer simulation for a perpendicular magnetic recording channel with bit flipping burst-like signal degradation, and it is compared with that of the RS encoding and decoding system using the erasure correction. The results show that the LDPC coding and iterative decoding system with our burst detector shows the better performance and has the resistance to the bit flipping burst-like signal degradation of about 1500 bits.

DOI： 10.1109/TMAG.2008.2002424

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

A new design method of the simplified neural network equalizer (NNE) with the noise whitening function for a generalized partial response (GPR) channel is proposed. The long-term bit error rate performance of GPR class-I maximum likelihood (GPR1ML) system employing NNE in perpendicular magnetic recording (PMR) channel with thermal decay is also obtained by computer simulation using our thermal decay model for a CoPtCr-SiO2 PMR medium with KuV/kT = 60. The performance of GPR1ML system with NNE (GPR1ML-NNE) is superior to that of GPR1ML with a transversal filter equalizer. The PR1ML system using a noise whitening NNE and a two-state Viterbi detector provides almost equivalent performance to that of GPR1ML-NNE having a 16-state detector.

DOI： 10.1109/TMAG.2008.2002425

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

The bit-error rate (BER) performance of the generalized partial response maximum likelihood with autoregressive (GPRML-AR) channel model system in perpendicular magnetic recording (PMR) channel with thermal decay is obtained. The 128/130(0,16/8) run-length-limited (RLL) code is used as a recording code. The GPR channel consists of the PR1 channel followed by the reduction circuit of predicted noise. The BER performance is evaluated by computer simulation using a thermal decay model. The model has been obtained by using an approximate equation that represents amplitude degradation of the reproducing waveform with elapsed time based on the experimental data for CoPtCr-SiO(2) PMR media. The Viterbi detector with an AR channel model is employed. Furthermore, long-term degradation of the required SNR to achieve a BER of 10(-4) with elapsed time is obtained and the performance is compared with that of PR1ML system. The results show that the poorer the thermal stability of the medium becomes, the larger the SNR gain of the GPR1ML-AR system over the PR1ML system becomes. The SNR gain also increases with elapsed time. (C) 2008 Elsevier B. V. All rights reserved.

DOI： 10.1016/j.jmmm.2008.08.025

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Nonlinear transition shift (NLTS) influences the performance of PRML channels in perpendicular magnetic recording. For NLTS, it is thought that write pre-compensation is useful to write the transition at the intended position. In this paper, we study the influence of NLTS on the BER performance of GPRML channels and show the appropriate amount of pre-compensation for GPRML channels both with and without a post-processor (PP) to achieve better BER performance. The results show that the widening the shortest bit length by NLTS brings the BER improvement to GPRML channel and the write pre-compensation is useful for a GPRML channel with PP. (C) 2008 Elsevier B. V. All rights reserved.

DOI： 10.1016/j.jmmm.2008.08.028

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

In this paper, a low-density parity check (LDPC) coding and iterative decoding system is studied in perpendicular magnetic recording (PMR) with a bit-patterned medium. We propose the efficient iterative decoding algorithm attenuating reliability information, and evaluate the sector error rate (SER) performance of the LDPC coding and iterative decoding system by R/W computer simulations. It is clarified that the proposed systems provide better SER performances than that of the conventional system at an areal density of 1 Tbit/in(2) and can also prevent the error floor which appears in the performance of conventional system. (C) 2008 Elsevier B. V. All rights reserved.

DOI： 10.1016/j.jmmm.2008.08.024

Web of Science

researchmap

Authorship：Lead author   Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

In this paper, a burst detection scheme using a parity check matrix of LDPC code is described for the perpendicular magnetic recording using a bit-pattered medium. It is assumed that the burst-like bit-flipping occurs due to missing the write synchronization. The phenomenon cannot be detected as a signal decay and significantly degrades the performance of the LDPC coding and iterative decoding system. Therefore, a good alternative detector is required in order to keep the performance. The LDPC coding and iterative decoding system is evaluated by the computer simulation in a perpendicular magnetic recording channel using a bit-patterned medium with the burst-like bit-flipping. It is clarified that the LDPC coding and iterative decoding system with a burst detector has the resistance to a burst-like bit-flipping of 200 bits.

DOI： 10.1109/ISITA.2008.4895390

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

The neural network equalization for polytopic multiplexing holography is studied to reduce interpixel interference. The bit error rate performance of the bilinear or bicubic interpolator followed by a neural network as an equalizer is obtained by computer simulation. The results show that the neural network equalizer provides an SNR improvement of about 1.0 dB over conventional equalization.

DOI： 10.1093/ietele/e90-c.8.1612

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

The long-term bit error rate (BER) performance of partial response maximum likelihood (PRML) system using an adaptive equalizer in a perpendicular magnetic recording (PMR) channel with thermal decay is studied. A thermal decay model based on the experimental data giving the amplitude change of reproducing waveforms with the elapsed time for CoPtCr-SiO2 PMR medium is obtained. The BER performance of PRIML channel for the 16/17(0,6/6) run-length-limited (RLL) code is evaluated by computer simulation using the model. The relationship between the ratio R-J of the jitter-like media noise power to the total noise power at the reading point and the required SNR to achieve a BER of 10(-4) is also obtained and the performance is compared with that of the conventional equalization. The results show that the significant improvement in SNR by utilizing the adaptive equalization is recognized over all R-J compared with the conventional equalization.

DOI： 10.1093/ietele/e90-c.8.1583

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

The long-term bit error rate (BER) performance of partial response maximum likelihood (PRML) system in a perpendicular magnetic recording (PMR) channel with thermal decay is studied. A thermal decay model based on the experimental data for three CoPtCr-SiO2 PMR media with different thermal stability is obtained. Then, the performance of PR1ML channel for the 16/17(0,6/6) and 128/130(0,16/8) codes as a run-length-limited (RLL) code is evaluated by computer simulation using the model. Moreover, the relationships between the elapsed time and the BER are obtained for the combinations of two RLL codes and three PMR media and their performances are compared. The results show that for the combination of the 128/130(0,16/8) code and the medium with the poorest thermal stability, the degradation with the elapsed time is noticeable compared with the other combinations.

DOI： 10.1109/TMAG.2007.893422

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

An LDPC coding and iterative decoding system is studied in perpendicular magnetic recording (PMR) with a bit-patterned medium. We propose an iterative decoding scheme using attenuated extrinsic information from a sum-product decoder, and the bit error rate (BER) performance of the LDPC coding and iterative decoding system is evaluated by R/W computer simulations. It has been clarified that at an areal density of 1 Tbpsi the proposed system provides a jitter margin of the island edges of approximately 0.6% larger than the conventional system using (3, 18)-regular LDPC code.

DOI： 10.1109/TMAG.2007.893421

Web of Science

researchmap

Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Publishing type：Research paper (scientific journal)  

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

In this paper, post-processors for the partial-response maximum-likelihood (PRML) channel combined with the Reed-Solomon (RS) encoder/decoder are studied in perpendicular magnetic recording. The bit error rate (BER) performance is obtained by read/write experiments using a spin-stand with a perpendicular medium and single-pole-type/giant magnetoresistive (SPT/GMR) head. The experimental results show that post-processors improve linear densities of about 10-20 kBPI in perpendicular magnetic recording. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jmmm.2004.10.067

Web of Science

researchmap

Language：Japanese   Publisher：The Magnetics Society of Japan  

In a hard disk drive (HDD), a postprocessor is used for correcting the random error in a PRML (Partial Response Maximum Likelihood) channel. However, the postprocessor needs an error-detecting code, such as a single parity check code, and the code rate decreases. This paper proposes an erasure correction by Reed-Solomon (RS) code using Squared-Distance-Increase (SDI) instead of a postprocessor. This system does not need any error detecting code. The performance is obtained by computer simulation and is compared with that of the error correction system using a postprocessor. The results show that the proposed system provides an SNR improvement of about 2.6dB compared with the system using a postprocessor in a perpendicular magnetic recording channel with random and burst errors.

DOI： 10.3379/jmsjmag.29.101

CiNii Books

researchmap

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10466920

Language：Japanese   Publisher：The Magnetics Society of Japan  

It is known that jitter-like noise in perpendicular magnetic recording system is large compared with longitudinal magnetic recording system. In this paper, the recording density and the amount of magnetic transition-jitter from the signal processing point of view are assumed to be same in both recording systems, and the performance comparison of GPRML systems are performed. It is clarified that the perpendicular magnetic recording system shows the good BER performance compared with the longitudinal magnetic recording system, and it has large allowance of magnetic transition-jitter.

DOI： 10.3379/jmsjmag.29.432

CiNii Books

researchmap

Other Link： http://dl.ndl.go.jp/info:ndljp/pid/10467017

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE Computer Society  

DOI： 10.1109/intmag.2005.1463929

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

In this paper, the interactive processing between a partial-response maximum-likelihood (PRML) channel and a decoder for the Reed-Solomon (RS) code is studied in perpendicular magnetic recording channel. Whereas in conventional systems a run-length-limited (RLL) encoder/decoder is insides the RS encoder/decoder, in this paper, we permute their positions so that the PRML channel and RS decoder can interact. Accordingly, the RS decoder can acquire reliability information from a PRML, channel without interruption by the RLL decoder. It is demonstrated by computer simulation that the proposed system proAdes an SNR improvement of 0.8-1.1 dB compared vvith a conventional system at a linear density normalized by user bit interval, K, of 1.5.

DOI： 10.1109/TMAG.2004.829284

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

Turbo decoding with an embedded autoregressive (AR) channel model is studied in an actual perpendicular magnetic recording channel. Performance of the a posteriori probability (APP) decoder is improved by applying an, AR channel model in order to estimate the decoder input sequence. The bit-error-rate (BER) performance,is obtained by read/write experiments using a spin stand with a perpendicular medium and an single-pole-type/giant magnetoresistive (SPT/GMR) head. The results show that our turbo coding and iterative decoding system using an AR channel model improves the BER performance.

DOI： 10.1109/TMAG.2003.816482

Web of Science

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

researchmap

Language：English  

researchmap

Language：English  

researchmap

Language：Japanese   Publisher：東京 : 映像情報メディア学会  

CiNii Books

CiNii Research

researchmap

Other Link： http://id.ndl.go.jp/bib/029116208

Language：Japanese   Publisher：東京 : 電子情報通信学会  

CiNii Books

CiNii Research

researchmap

Other Link： http://id.ndl.go.jp/bib/029084816

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：English  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese   Publisher：映像情報メディア学会  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：English   Publisher：Institute of Image Information and Television Engineers  

Tape systems experience large speed variations compared to disk systems, and therefore, it is necessary to design a stable timing recovery scheme that can operate under a low signal-to-noise ratio (SNR) condition. In such low SNR scenarios, the decision error made by the detector often results in a phase-locked loop circuit losing track of the correct signal. This phenomenon is often called the loss-of-lock (LOL) phenomenon. In order to mitigate the LOL issue, soft information from the soft output Viterbi algorithm decoder is used to control the feedback in the timing recovery loop. Therefore, a timing recovery method for high-density tape storage system is studied in this paper. By applying this new method to the read back signal from the actual tape drive, it is verified that the negative effect of misdetection due to unreliable decisions from the detector can be compensated, with only a minor increase in implementation complexity.

DOI： 10.3169/mta.4.296

Scopus

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

researchmap

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

researchmap

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Two-dimensional magnetic recording (TDMR) by shingled magnetic recording (SMR) exploits two-dimensional signal processing using the waveforms reproduced by array head from intended and adjacent tracks. However, array head has the issue on the degradation of bit error rate (BER) performance due to head skew. In this report, we evaluate the BER performance of SMR R/W channel with head skew under the specification of 4 Tbit/inch^2 by low-density parity-check (LCPD) coding and iterative decoding system with the equalizer using the two-dimensional finite impulse response (TD-FIR) filter for multiple read-back waveforms.

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Timing recovery method for high density tape storage system is studied. Since tape system suffers from large speed variation compared to the disk system, the design of a stable PLL circuit which can operate under low signal to noise ratio (SNR) condition is an important issue. In such low SNR circumstance, the decision error made by the detector sometimes leads PLL circuit to lose its track on the correct signal, which is often called the cycle-slip phenomenon. In order to mitigate cycle-slip issue, soft information from the Viterbi detector is utilized. It is clarified that the negative effect of un-reliable decision from the detector can be compensated by controlling the feedback gain of the timing recovery loop dynamically as a function of decision reliability.

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese  

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese  

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

A measurement method of nonlinear transition shift (NLTS) and the write precompensation in the shingled magnetic recording (SMR) are studied. In SMR R/W channel using a discrete granular medium composed of the discrete Voronoi diagram, we measure the NLTS and show had the previous track influences to the NLTS of the current track. We propose a new write precompensation by considering the recording sequence in previously recorded adjacent track, and evaluate our proposed write precompensation method by the remained NLTS and the bit error rate (BER) performance for the SMR R/W channel under a recording density of 4 Tb/in2. It is clarified that our proposed write precompensation method prevents the NLTS, however the BER performance a little degrades compared with that of the case without the write precompensation.

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

MR2012-1

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：English  

MR2011-28

CiNii Books

researchmap

Language：Japanese  

MR2011-26<br />

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

MR2011-5

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

MR2011-7

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese  

MR2010-46

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

MR2010-30

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

MR2010-3

DOI： 10.11485/itetr.34.20.0_21

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

MR2010-11

DOI： 10.11485/itetr.34.20.0_73

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

The neuro-interpolator (NI) integrating an interpolator with a neural network equalizer in holographic data storage is proposed to reduce the influence of interpixel interference due to the aperture restriction which limits the effective recording area on the holographic medium. The simplification of NI is performed by using a hybrid genetic algorithm based on a new mutation method introducing a pruning probability, and its bit error rate (BER) performance is studied by computer simulation. The results show that the BER performance of simplified NI is superior to that of the interpolator alone. Furthermore, the number of connections in the simplified NI is reduced to about half of that obtained by using a conventional mutation method. In addition, the proposed mutation method shows the slightly-improved performance over the conventional one.

DOI： 10.11485/itetr.34.20.0_67

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

MR2009-40

DOI： 10.11485/itetr.33.57.0_19

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

MR2009-11

DOI： 10.11485/itetr.33.22.0_59

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

MR2008-41

DOI： 10.11485/itetr.32.55.0_19

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

MR2008-26

DOI： 10.11485/itetr.32.41.0_43

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

MR2008-27

DOI： 10.11485/itetr.32.41.0_49

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

MR2008-14

DOI： 10.11485/itetr.32.28.0_21

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

MR2008-7

DOI： 10.11485/itetr.32.23.0_35

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：愛媛大学工学部  

CiNii Books

researchmap

Language：Japanese  

MR2007-47

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese  

MR2007-37

researchmap

Language：Japanese  

MR2007-23

researchmap

Language：Japanese  

MR2007-10

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：English   Publisher：Ehime University  

Partial response maximum likelihood (PRML) channels are studied in R/W channels using bit-patterned media. Bit error rate (bER) performance and error events of generalized PRML (GPRML) systems with a noise predictor are evaluated. The bER performance obtained by computer simulation shows that the GPR channel based on full-response channel shows good performance. In addition, the error events of GPRML systems in the R/W channel using double layered bit-patterned medium are compared with those of continuous medium, and it is clarified by the error event characteristics that the two kinds of R/W channels using bit-patterned and continuous media have quite different characteristics.

CiNii Books

researchmap

Other Link： http://iyokan.lib.ehime-u.ac.jp/dspace/handle/iyokan/1483

researchmap

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

The neural network equalization is proposed to reduce the influence of interpixel interference due to aperture restriction in polytopic multiplexing. The proposed method improves the SNR by about 1.8dB over that of conventional method.

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese  

通研インポート200703

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

通研インポート200703

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

通研インポート200703

CiNii Books

researchmap

Language：Japanese  

通研インポート200703

researchmap

Language：English   Publisher：The Institute of Electronics, Information and Communication Engineers  

通研インポート200703

CiNii Books

researchmap

Language：Japanese  

通研インポート200703

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

The performance of LDPC coding and iterative decoding system is evaluated in a perpendicular magnetic recording channel with burst-like signal degradation. In this report, a new LDPC decoder with burst position and length detector is proposed. The relationship between the burst length and the required SNR to perform the detection without error in a given data sequence for the proposed system is obtained by computer simulation, and compared with that for the conventional system. The results show that the proposed system has the tolerance to the burst over about 350 channel bits, while the conventional system has that over only about 150 channel bits at SNR = 23dB.

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Advances in signal processing techniques have played a significant role in the recent remarkable increases in data storage density of the hard disk drives (HDDs). Though the shipment of HDDs employing perpendicular magnetic recording is drawing near, the PRML systems are still important signal processing techniques to increase the recording density in perpendicular magnetic recording as well as in longitudinal magnetic recording which is employed in present HDDs. This report mainly presents the PRML systems for perpendicular magnetic recording, i.e., the history of signal processing techniques for magnetic recording, the R/W channel of perpendicular magnetic recording, the positive coefficients PRML system, the DC-unbalanced PRML system, the noise predictive PRML system and the neuro PRML system.

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

The LDPC decoder for perpendicular magnetic recording channel with burst is studied. A new sumproduct LDPC decoder with a burst position and length detector is proposed. The proposed system has the tolerance to a burst of 400 bits, while the conventional system has that of only 150 bits.

DOI： 10.11485/iteac.2005.0__2-1-1_

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

An important issue in perpendicular magnetic recording is the performance degradation of PRML system due to the influence of the data dependent noise such as jitter-like medium noise. In this report, the neural network equalization is studied to mitigate the influence of jitte-like medium noise. A method of simplification of neural network using a hybrid genetic algorithm(GA) is proposed. Then, the bit error rate performance for PR2ML system with a simplified neural network equalizer is obtained and compared with those of conventional neural network and transversal filter equalizers. The results show that the SNR improvements of PR2ML systems with simplified neural network equalizer over PR2ML system with conventional neural network and transversal filter equalizers are about 0.8 and 1.0 dB, respectively.

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Image Information and Television Engineers  

Performance improvement of an APP decoder in a serially concatenated turbo coding and decoding system is studied in perpendicular magnetic recording. An estimator of output levels from a PR channel in APP decoder is improved, and BER performance is obtained by computer simulation. The results show that the performance is improved. It is also clarified that the performance improvement is obtained by extension of coding and decoding block size.

DOI： 10.11485/itetr.25.63.0_21

CiNii Books

researchmap

Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Performance improvement of an APP decoder in a serially concatenated turbo coding and decoding system is studied in perpendicular magnetic recording. An estimator of output levels from a PR channel in APP decoder is improved, and BER performance is obtained by computer simulation. The results show that the performance is improved. It is also clarified that the performance improvement is obtained by extension of coding and decoding block size.

CiNii Books

researchmap

Event date： 2020.8

Language：English   Presentation type：Poster presentation  

researchmap

Event date： 2020.8

Language：English   Presentation type：Oral presentation (invited, special)  

researchmap

Event date： 2020.5

Language：English   Presentation type：Poster presentation  

researchmap

Event date： 2020.5

Language：English   Presentation type：Poster presentation  

researchmap

Event date： 2019.11

researchmap

Event date： 2019.7

Language：English  

researchmap

Event date： 2019.7

Language：English  

researchmap

Event date： 2015.8

researchmap

Event date： 2015.5

Language：Japanese  

researchmap

Event date： 2014.12

Language：Japanese  

researchmap

Event date： 2014.11

researchmap

Event date： 2014.6

Language：Japanese  

researchmap

Event date： 2013.6

Language：Japanese  

researchmap

Event date： 2012.6

Language：Japanese  

MR2012-1

researchmap

Event date： 2012.3

Language：Japanese  

researchmap

Event date： 2011.12

Language：English  

MR2011-28

researchmap

Event date： 2011.12

Language：Japanese  

MR2011-26<br />

researchmap

Event date： 2011.7

Language：Japanese  

MR2011-5

researchmap

Event date： 2011.7

Language：Japanese  

MR2011-7

researchmap

Event date： 2010.12

Language：Japanese  

MR2010-46

researchmap

Event date： 2010.10

Language：Japanese  

MR2010-30

researchmap

Event date： 2010.6

Language：Japanese  

MR2010-3

researchmap

Event date： 2010.6

Language：Japanese  

MR2010-11

researchmap

Event date： 2009.12

Language：Japanese  

MR2009-40

researchmap

Event date： 2009.6

Language：Japanese  

MR2009-11

researchmap

Event date： 2008.12

Language：Japanese  

MR2008-41

researchmap

Event date： 2008.10

Language：Japanese  

MR2008-26

researchmap

Event date： 2008.10

Language：Japanese  

MR2008-27

researchmap

Event date： 2008.7

Language：Japanese  

MR2008-14

researchmap

Event date： 2008.6

Language：Japanese  

MR2008-7

researchmap

Event date： 2008.3

Language：Japanese  

researchmap

Event date： 2008.1

Language：Japanese  

MR2007-47

researchmap

Event date： 2008

researchmap

Event date： 2008

researchmap

Event date： 2008

researchmap

Event date： 2007.4

Language：Japanese  

MR2007-10

researchmap

Event date： 2007.4

Language：Japanese  

MR2007-37

researchmap

Event date： 2007.4

Language：Japanese  

MR2007-23

researchmap

Event date： 2007

researchmap

Event date： 2007

researchmap

Event date： 2006

Language：English  

通研インポート200703

researchmap

Event date： 2006

Language：Japanese  

通研インポート200703

researchmap

Event date： 2006

Language：Japanese  

通研インポート200703

researchmap

Event date： 2006

Language：Japanese  

通研インポート200703

researchmap

Event date： 2006

Language：Japanese  

通研インポート200703

researchmap

Event date： 2006

Language：Japanese  

通研インポート200703

researchmap

Event date： 2005

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：English   Presentation type：Poster presentation  

researchmap

Language：Japanese  

researchmap

Language：Japanese   Presentation type：Oral presentation (general)  

researchmap

Language：English   Presentation type：Poster presentation  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：English   Presentation type：Oral presentation (general)  

researchmap

Language：English   Presentation type：Oral presentation (invited, special)  

researchmap

Language：Japanese  

researchmap

Language：English   Presentation type：Oral presentation (general)  

researchmap

Language：English   Presentation type：Poster presentation  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：English   Presentation type：Poster presentation  

researchmap

Language：Japanese   Presentation type：Oral presentation (invited, special)  

researchmap